Prior art network architectures are shown in FIGS. 1-3. FIG. 1 shows a star network where a central device 10 is coupled as shown to a network device 11, a network device 12, a network device 13, a network device 14, a network device 15, and a network device 16. FIG. 2 shows a bus network where central device 10 and network devices 11-16 are all coupled as shown to a bus 20. Star and bus type networks are limited in that they require that there exist for every network device 11-16 an information path directly to central device 10.
In FIG. 3 central device 10 and network devices 11-16 are coupled in a loop network. In the loop network shown in FIG. 3, information flows around the loop in a clockwise direction. Therefore, in order for central device 10 to communicate with network device 15, a message is passed from central device 10 through network device 11, through network device 12, through network device 12, through network device 14, to network device 15. Network device 15 may send a message through network device 16 to central device 10 to acknowledge receipt of the message.
The addition of network devices to the star network shown in FIG. 1 may be limited by available connection ports to central device 10. Similarly, the addition of network devices to the bus network shown in FIG. 2 may be limited by available connection ports to bus 20. However, unlimited network devices may be added to the loop network shown in FIG. 3. In order to add a network device 17 between network device 16 and central device 10 the output of network device 16 could be directed into network device 17 and the output of network device 17 could be directed into central device 10.